Stripped thread torsion bar cover

[Mike_72]

I have some stripped threads on a couple of the bolts which attach the cover for the torsion bar and spring plate and I am looking for some advice on what to do to fix them. I have searched and not found any other cases of this, I find it hard to believe this hasn't happened to someone before. I am considering repairing with a hell coil but I am worried that once drilled and tapped to accept the M10x1.50 insert there won't be much material left and strength will be greatly reduced. Let me know if you guys have any ideas.

[metalracer]

I'm surprised this topic isn't brought up more often too. I've had to deal with a number of cars with this problem. In many cases, I was luck and the stripped portion was only first few threads. So, I just ran a longer bolt and things were solid. I've also been able to chase threads with a thread chaser (different than a tap) with reasonable success.

If none of that works for you and you must replace the threads, I think you'll be fine using a real wound-wire heli-coil. But not the bulky thread inserts!

Good luck!!

[Mike_72]

I am considering using a 7/16-20 bolt to replace the M10 as it appears the stripped threads leave me with pretty close to what the drill size would be for a 7/16-20 tap. My main concern is the amount of material that will be left after tapping the hole to the new size.

[Kraftwerk]

Resurrecting this older thread..... speaking of threads mine are are stripped on the lower left, "only" two out of four @ cover for the torsion bar and spring plate have compromised threads UGH. Just want to button this back up. Almost done. Now, I should tap this out. The thread chaser went off-course and 'chased' the thing at an angle. It's a nightmare.. some days go so smoothly other days it's ****e! Who makes the best taps for this?

[GenX Porsche]

This zombie thread is hitting home for me... I snapped a bolt off on the driver lower side and have been ignoring it... then I drilled it out and tried an easy out and broke that off in there, I am confident it will come out. Any tips regarding fixing the threads are appreciated. I have thought about cutting the threaded portion off the body and rewelding a female bung but that seems extreme.

[Kraftwerk]

Zombie problems never die. I think two things lead to the mis-threading:
1. When the area gets a fresh coat of paint, say, during a suspension overhaul, several coats of fresh paint get in the female threads, that can't be beneficial.
2. If the torsion bar is 'active' it will cause the whole plate to turn, holes in the plate will push the bolts off-course. Should install everything with zero tension on the plate.

Which to buy? What to look for in a Tap, material etc. ? hmm the Balax is $355. each!
Solid Carbide, Thread Forming, Bright Tap Finish

From the Grainger site:
"These taps feature solid carbide construction and are designed to form the threads instead of cutting them. The design helps to eliminate chipping and is suitable for both through holes and blind holes."

BALAX Tap Dimension Type: MetricTap Thread Size Pitch Diameter Limit Tap Chamfer Number of Flutes Tap Thread Type Item #

M12-1.75 Not Rated Bottoming 0 Metric Coarse 35XM57
Regular Price $355.00 / each"

Then there is CLEVELAND, EMUGE, GREENFIELD THREADING, probably the cheapest is IRWIN / HANSON
I am in the forrest here...

[Walt Fricke]

It is a bit hard to know just what the "nut" part of this connection is like, since you can't readily see inside the chassis longitudinal. I suppose a guy could drill a hole on the backside, and use a borescope. Maybe someone who did surgery on this part of the tub has a picture?

But I'd try the thread chasing and longer bolt. If that doesn't work, put in the Heli-coil. If that doesn't work (my bet is that it will, but don't know), try something else.

For instance, thake a spare 911 10mm head bolt barrel nut (if you lived near me, I'd give you one - I've got a jar full as I use flange nuts instead), turn its back end down so you have a flange on the hex head end, drill your bolt hole to fit, and weld the flange in place. You would need to shorten the spacer, but so what.

Or make something like this from rod stock if you have a lathe and taps.

[HaroldMHedge]

Lang/Kastar has a nice 48 Pc. SAE and Metric Thread Restorer Kit SKU 971. Check around on the web and it can be found for about half the list price.

Time-sert or key type locking insert (Ex. Keyserts, Keensert) maybe a better option than a Heli-coil.

[Kraftwerk]

Walt, Thanks for chiming in, I think these stud's are rather short not much depth...Looks like there is room for a longer stud, if ever I would get one welded in there.

Harold, Thanks- that Lang/Kastar 48 Pc. SAE and Metric Thread Restorer Kit SKU 971. is pretty much the exact same set I have (cheaper from Harbor-Frieght.) It's great for cleaning threads but not a true 'tap'. Correct me if I am wrong, but I think the threaded part needs to be 'tapered' in order to properly 'lead-in' to the threads -cut it's way in... "tap ' its way in. The H/F kit has a "square-end " sufficient for correcting small wrongs, not a true cutting tool.

Keyserts look great, although I have never used them nor Heli-coil good to see these products exist.

Might end up seeking the services of an expert for this fix.